In order to avoid problems that a screen of a mobile phone can be seen clearly under strong light such as sun due to dimness of the screen and backlight of the screen of the mobile phone is too bright and too dazzling in dusky environments, a light sensor is added to the mobile phone to automatically change brightness of the backlight of the screen.
In the prior art, a specific implementation scheme in which the brightness of the screen of the mobile phone is varied with the change of the external brightness is described below.
The brightness of the external environment is detected to obtain an environment illumination brightness value to determine whether the obtained illumination brightness value is equal to the preceding obtained environment illumination brightness value. If the determination result is yes, the brightness of the screen of the mobile phone is maintained; otherwise, a processing unit determines whether the obtained environment illumination brightness value is greater than the preceding determined environment illumination brightness value. If the obtained environment illumination brightness value is greater than the preceding determined environment illumination brightness value, then the brightness of the screen of the mobile phone will be adjusted up. If the both determination results are negative, the brightness of the screen of the mobile phone will be adjusted down.